Anti-aircraft warfare, AAW, involves engaging hostile military aircraft in defense of ground objectives, ground or naval forces or denial of passage through a specific airspace region, area or anti-aircraft zone. It is also commonly used to deny entry into national airspace to unauthorized aircraft.
A significant cause for concern in AAW engagements prosecuted by ship-based or other weapon systems is the elimination, or at least reduction, of fratricide against friendly aircraft. The primary conventional method for preventing fratricide is by using the conventionally known IFF, Interrogate Friend or Foe, secondary radar system. IFF is an electronic system that uses radar to determine the intent of an aircraft, with the speed of a computer. Contemporary IFF is a two-channel system with one frequency, 1030 megahertz, generally used for the interrogating system and another frequency, commonly 1090 megahertz, used for the reply. The interrogating signals may be encrypted and the friendly aircraft includes a transponder. The transponder receives the interrogating signals and, responsive to an interrogating signal, send a return signal confirming the aircraft as friendly. In the case of an encrypted signal, the transponder decodes the encrypted message, validates the encrypted message and sends a coded or encrypted message back to the interrogating system which receives the return signal and confirms the validation of friendly aircraft.
There are at least two areas of concern regarding the use of IFF to minimize fratricide. An equipment failure on the targeted friendly aircraft would prevent it from successfully responding to IFF interrogations and there may be a need for the targeted friendly aircraft to maintain radio silence for operational considerations, such as would be the case when the possibility of radio transmissions might undesirably expose the aircraft to hostile fire.
It is of tantamount importance to reduce fratricide. The detrimental effects of fratricide and the fear thereof may include hesitation to conduct limited visibility operations, loss of confidence in a unit's leadership, increase of leader self doubt, hesitation to use supporting combat systems, oversupervision, loss of initiative, loss of aggressiveness during fire and maneuver, disrupted operations, needless loss of combat power and numerous other negative aspects.
The present invention provides a method and system that addresses the limitations associated with the use of IFF to minimize fratricide.